Understanding and reporting visual acuity measurements in publications of clinical research.

V isual acuity is an important measure for assessment of visual function. While there are many charts available to test visual acuity, there is lack of consistency in the methods of testing and methods of reporting visual acuity that may make comparisons difficult between visual outcomes among different published studies. In our opinion, most US ophthalmologists are familiar with the Snellen notation of visual acuity but have limited understanding of how other notations of visual acuity translate into Snellen notation. While some journals such as the American Journal of Ophthalmology provide charts to facilitate this translation, if the chart is not available at the time one is reading an article or listening to a presentation, understanding the level of visual acuity or changes in visual acuity may be limited.